Time to explore.
Writing is connected to the unknown, and when you get the urge to write, it's because you feel the need of exploring the depths of your being.
As you know, writing is exploring your inner being and the ability to tap into a larger reality. It's a vehicle for discovery, and very few other activities have the same depth.
When writing you create your own space of action while integrating your body, emotions, thoughts, and intuition in the same process.
In other words, all the elements are in play at the same time, and your cognitive faculties are running at full speed. You simply hit the flow-zone and surf the wave of whatever wants to be written. Just like you would surf a big wave on the ocean.